Display device, display control method, and non-transitory computer-readable recording medium

ABSTRACT

The disclosure provides a display device, a display control method, and a non-transitory computer-readable recording medium. The display device of an embodiment is mounted on a vehicle and includes: a display part; and a display controller displaying operation information related to downhill road travel control, which controls a speed of the vehicle traveling downhill to a constant speed, on the display part. The downhill road travel control switches from a standby state to an active state when an execution condition, including that input of an accelerator operation and a brake operation is stopped, is satisfied. The display controller displays by changing at least a part of a display mode of the operation information when the downhill road travel control is in the standby state and the input of the accelerator operation or the brake operation is stopped.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefits of Japanese applicationno. 2020-158574, filed on Sep. 23, 2020. The entirety of theabove-mentioned patent application is hereby incorporated by referenceherein and made a part of this specification.

BACKGROUND Technical Field

The disclosure relates to a display device, a display control method,and a non-transitory computer-readable recording medium.

Description of Related Art

In recent years, research has been conducted on automaticallycontrolling the traveling of vehicles. In connection with this, adownhill speed control device is known, which controls an amount ofbraking so that an actual vehicle speed matches a target vehicle speedat the time of downhill traveling (for example, see Patent Document 1).

RELATED ART Patent Document

[Patent Document 1] Japanese Laid-Open No. 2004-142689

Problems to be Solved

However, in the conventional technique, an occupant is not notified of arange that can be controlled by the control device. Therefore, it may bedifficult for the occupant to recognize a state of driving controlperformed by the control device.

SUMMARY

A display device, a display control method, and a non-transitorycomputer-readable recording medium according to the disclosure adopt thefollowing configurations.

(1): A display device according to one aspect of the disclosure ismounted on a vehicle. The display device includes: a display part; and adisplay controller displaying operation information related to downhillroad travel control, which controls a speed of the vehicle travelingdownhill to a constant speed, on the display part. The downhill roadtravel control is control that switches from a standby state to anactive state when an execution condition, which includes that input ofan accelerator operation and a brake operation is stopped, is satisfied.The display controller displays by changing at least a part of a displaymode of the operation information when the downhill road travel controlis in the standby state and the input of the accelerator operation orthe brake operation is stopped.

(2): In the aspect of (1) above, the display controller displays astandby state image showing that the downhill road travel control is inthe standby state when the downhill road travel control is in thestandby state, and displays an active state image having a differentdisplay mode from the standby state image and showing that the downhillroad travel control is in the active state when the downhill road travelcontrol is in the active state, and displays the active state imageinstead of the standby state image when the downhill road travel controlis in the standby state and the input of the accelerator operation orthe brake operation is stopped.

(3): In the aspect (1) or (2) above, the display controller displays bychanging at least a part of the display mode of the operationinformation when the downhill road travel control is in the active stateand the accelerator operation or the brake operation is input.

(4): In the aspect of (3) above, the display controller displays thestandby state image showing that the downhill road travel control is inthe standby state when the downhill road travel control is in thestandby state, and displays the active state image having a differentdisplay mode from the standby state image and showing that the downhillroad travel control is in the active state when the downhill road travelcontrol is in the active state, and displays the standby state imageinstead of the active state image when the downhill road travel controlis in the active state and the accelerator operation or the brakeoperation is input.

(5): In the aspect (2) or (4) above, the standby state image is an imagethat displays at least part of the operation information in a whitecolor, and the active state image is an image that displays at leastpart of the operation information in a green color.

(6): In any aspect of (1) to (5) above, the display controller displaysboth an icon image showing a state of the downhill road travel controland a wording image showing the state of the downhill road travelcontrol as the operation information.

(7): A display control method according to another aspect of thedisclosure is for a computer of a display device mounted on a vehicleto: display operation information related to downhill road travelcontrol, which controls a speed of the vehicle traveling downhill to aconstant speed, on a display part, wherein the downhill road travelcontrol is control that switches from a standby state to an active statewhen an execution condition, which includes that input of an acceleratoroperation and a brake operation is stopped, is satisfied; and display bychanging at least a part of a display mode of the operation informationwhen the downhill road travel control is in the standby state and theinput of the accelerator operation or the brake operation is stopped.

(8): A non-transitory computer-readable recording medium recording aprogram according to another aspect of the disclosure is for a computerof a display device mounted on a vehicle to: display operationinformation related to downhill road travel control, which controls aspeed of the vehicle traveling downhill to a constant speed, on adisplay part, wherein the downhill road travel control is control thatswitches from a standby state to an active state when an executioncondition, which includes that input of an accelerator operation and abrake operation is stopped, is satisfied; and display by changing atleast a part of a display mode of the operation information when thedownhill road travel control is in the standby state and the input ofthe accelerator operation or the brake operation is stopped.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a configuration diagram of the vehicle system 1 including thecontrol device according to an embodiment.

FIG. 2 is a diagram schematically showing the interior of the vehicle M.

FIG. 3 is a diagram for illustrating the HDC executed by the drivingcontroller 140.

FIG. 4 is a diagram showing an example of the images displayed on thedisplay device 32 at the times t1 to t3.

FIG. 5 is a diagram showing an example of the images displayed on theIND and the MID at the time t3.

FIG. 6 is a diagram for illustrating an example of the display mode thatchanges according to whether the accelerator operation or the brakeoperation is performed.

FIG. 7 is a diagram for illustrating a first example of display controlwhen the target vehicle speed is changed.

FIG. 8 is a diagram for illustrating a second example of display controlwhen the target vehicle speed is changed.

FIG. 9 is a diagram for illustrating a third example of display controlwhen the target vehicle speed is changed.

FIG. 10 is a diagram for illustrating an example of display control whenthe target vehicle speed is changed after the time t3e.

FIG. 11 is a diagram for illustrating display control based on a statechange of driving control after the time t4.

FIG. 12 is a diagram showing other examples of the operation informationdisplayed on the display device 32.

FIG. 13 is a diagram showing other examples of the operation informationdisplayed on the display device 32.

FIG. 14 is a flowchart showing an example of the flow of processingexecuted by the driving support device 100 of an embodiment.

FIG. 15 is a flowchart showing an example of the flow of processing ofchanging the target speed.

DESCRIPTION OF THE EMBODIMENTS

According to an embodiment of the disclosure, it provides a displaydevice, a display control method, and a non-transitory computer-readablerecording medium that make it easy for the occupant to recognize thestate of driving control.

Hereinafter, embodiments of a display device, a display control method,and a program of the disclosure will be described with reference to thedrawings. The embodiments illustrate an example in which a state ofdriving control for a vehicle is displayed on the display device whenthe driving control of the vehicle is performed. The driving controlrefers to, for example, controlling at least one or both of the steeringand speed of the vehicle. The driving control includes, for example, CC(Cruise Control) that travels at a constant speed, ACC (Adaptive CruiseControl) that follows a preceding vehicle, LKAS (Lane Keeping AssistanceSystem) that travels by keeping the traveling lane, etc. In addition, CCincludes, for example, HDC (Hill Descent Control) and DAC (DownhillAssist Control) that perform constant speed traveling at a predeterminedspeed or lower, without being operated by an occupant, on a slope suchas a downward slope (downhill). The HDC and DAC are examples of“downhill road travel control” that controls the speed of a vehicletraveling downhill to a constant speed. HDC may be referred to as hilldescent control.

[Overall Configuration]

FIG. 1 is a configuration diagram of a vehicle system 1 using thedisplay device according to the embodiment. A vehicle on which thevehicle system 1 is mounted (hereinafter referred to as vehicle M) is,for example, a two-wheeled vehicle, a three-wheeled vehicle or afour-wheeled vehicle, and a drive source thereof includes an internalcombustion engine such as a diesel engine or a gasoline engine, anelectric motor or a combination of these. The electric motor operates byusing electric power generated by a generator connected to the internalcombustion engine or electric power discharged by a secondary battery ora fuel cell.

The vehicle system 1 includes, for example, a camera 10, a radar device12, an HMI (Human Machine Interface) 30, a vehicle sensor 40, a drivingoperator 80, a driving support device 100, a traveling driving forceoutput device 200, and a brake device 210. These devices and machinesare connected to each other by a multiplex communication line such as aCAN (Controller Area Network) communication line, a serial communicationline, a wireless communication network, etc. The configuration shown inFIG. 1 is merely an example, and a part of the configuration may beomitted or another configuration may be added. The combination of theHMI 30 and an HMI controller 150 described later is an example of“display device”.

The camera 10 is, for example, a digital camera using a solid-stateimaging element such as a CCD (Charge Coupled Device) and a CMOS(Complementary Metal Oxide Semiconductor). The camera 10 is attached toany position on the vehicle M. When imaging the front, the camera 10 isattached to the upper part of a front windshield or the back surface ofa rearview mirror. The camera 10 periodically and repeatedly images theperiphery of the vehicle M, for example. The camera 10 may be a stereocamera.

The radar device 12 radiates radio waves such as millimeter waves to theperiphery the vehicle M, and detects radio waves (reflected waves)reflected by an object to detect at least the position (distance andorientation) of the object. The radar device 12 is attached to anyposition on the vehicle M. The radar device 12 may detect the positionand speed of the object by FMCW (Frequency Modulated Continuous Wave).

The HMI 30 presents various information to an occupant of the vehicle M(which may be a driver or a passenger) and accepts an input operation ofthe occupant. The HMI 30 includes, for example, a display device 32, adriving support switch 34, and a display changeover switch 36. Thedisplay device 32 is an example of “display part”. Further, the HMI 30may include a speaker, a microphone, a buzzer, a touch panel, etc. Thedriving support switch 34, the display changeover switch 36, themicrophone, and the touch panel are examples of “reception part”.

FIG. 2 is a diagram schematically showing the interior of the vehicle M.The display device 32 has, for example, a first display part 32A and asecond display part 32B. The first display part 32A and the seconddisplay part 32B may be, for example, indicators (hereinafter referredto as “IND” if necessary) that display the state of the vehicle M or anin-vehicle device by a simple LED (Light Emitting Diode) display or thelike, or may be MIDs (Multi Information Display). In the case of MID,the first display part 32A and the second display part 32B are, forexample, LCDs (Liquid Crystal Display), organic EL (Electroluminescence)display devices, etc. The images displayed on the first display part 32Aand the second display part 32B are controlled by the HMI controller150.

The first display part 32A is provided, for example, near the front ofthe driver's seat (the seat closest to a steering wheel SW) in aninstrument panel IP, and is installed at a position where the occupantcan see through a gap of the steering wheel SW or through the steeringwheel SW. On the first display part 32A, information (hereinafterreferred to as operation information) related to the manual driving ofthe vehicle M or the driving control of the driving controller 140 isdisplayed as an image.

The information required for the traveling of the vehicle M during themanual driving refers to, for example, the speed of the vehicle M, theengine speed, the remaining fuel amount, the radiator water temperature,the mileage, and other information.

The information (operation information) related to the driving controlrefers to, for example, information related to the state of the drivingcontrol, information related to the recognition result of a recognitionpart 120 and the detection result of the vehicle sensor 40. The state ofthe driving control includes, for example, a state where the drivingcontroller 140 is not operating (off state), a state where the drivingcontroller 140 is in operation and waiting for the start of execution ofthe driving control (standby state), and a state where the drivingcontrol of the driving controller 140 is being executed (active state).Although the details will be described later, the downhill road travelcontrol is control that switches to the standby state when apredetermined operation condition is satisfied after a switch operationis formed, and switches to the active state when a predeterminedexecution condition is satisfied in the standby state. The display modeof the information will be described in detail later.

The information related to the recognition result of the recognitionpart 120 and the detection result of the vehicle sensor 40 includes, forexample, information related to the posture (vehicle body posture) ofthe vehicle M, information related to the slope (gradient) of thetraveling road, information related to the lane (road lane marking),etc. Further, the information related to the driving control may includea part or all of the information required for the traveling of thevehicle M during the manual driving.

The second display part 32B is installed in the center of the instrumentpanel IP, for example. The second display part 32B displays informationthat can be displayed by the first display part 32A. Further, the seconddisplay part 32B may display an image of the navigation result of anavigation device (not shown), an image read from a television programor a DVD, and a content such as a movie downloaded from an externaldevice via an in-vehicle communication device (not shown).

Returning to FIG. 1, the driving support switch 34 is a switch thatreceives a start instruction or an end instruction of the drivingcontrol (for example, downhill road travel control, etc.) performed bythe driving controller 140 for the vehicle M. The driving support switch34 receives the start instruction or the end instruction of the drivingcontrol by an on/off switch or the like by the operation of the occupantof the vehicle M. The driving support switch 34 may be provided, forexample, for each type of driving control executed by the drivingcontroller 140. The display changeover switch 36 is a switch forswitching between display and non-display of an image on the displaydevice 32. The driving support switch 34 and the display changeoverswitch 36 may be, for example, a GUI (Graphical User Interface) switchdisplayed on the display device 32 or a mechanical switch such as a dialtype switch, a lever type switch, and a button type switch. When thedriving support switch 34 is a mechanical switch, the type of thedriving control can be specified according to the length of time theswitch is continuously pressed, the number of times the switch ispressed, and the position where the switch is pressed.

The vehicle sensor 40 includes a position sensor that detects theposition of the vehicle M, a vehicle speed sensor that detects thevehicle speed, a yaw rate sensor that detects an angular speed aroundthe vertical axis, an orientation sensor that detects the direction ofthe vehicle M, etc. The position sensor is, for example, a GNSS (GlobalNavigation Satellite System) receiver that identifies the position (forexample, latitude and longitude) of the vehicle M based on a signalreceived from a GNSS satellite. Further, the vehicle sensor 40 mayinclude a G sensor capable of acquiring a change status of the vehiclebody posture due to acceleration, deceleration, and load of the vehicleM. For example, the G sensor can detect the inclination of the vehicle Mby measuring the speed change with respect to three axes such as up anddown, left and right, and front and back. In addition, the vehiclesensor 40 may detect the posture of the vehicle M by comparing thedegree of load of a suspension system provided for each wheel.

The driving operator 80 includes, for example, an accelerator pedal, abrake pedal, a shift lever, the steering wheel SW, a directionindicator, a joystick, and other operators. A sensor that detects theoperation amount or whether an operation is performed is attached to thedriving operator 80, and the detection result thereof is output to thedriving support device 100 or some or all of the traveling driving forceoutput device 200, the brake device 210, and a steering device (notshown).

The driving support device 100 includes, for example, the recognitionpart 120, a determination part 130, the driving controller 140, the HMIcontroller 150, and a storage part 160. The recognition part 120, thedetermination part 130, the driving controller 140, and the HMIcontroller 150 are realized by, for example, a processor such as a CPU(Central Processing Unit) or a GPU (Graphics Processing Unit) executinga program (software). In addition, some or all of these components maybe realized by hardware (circuit part; including circuitry) such as LSI(Large Scale Integration), ASIC (Application Specific IntegratedCircuit), and FPGA (Field-Programmable Gate Array), or may be realizedby collaboration of software and hardware. The program may be stored inthe storage part 160 of the driving support device 100 in advance, ormay be stored in a removable storage medium such as a DVD or a CD-ROMand installed in the storage part 160 by mounting the storage medium ona drive device. The HMI controller 150 is an example of “displaycontroller”.

The storage part 160 is realized by, for example, an HDD, a flashmemory, an EEPROM (Electrically Erasable Programmable Read Only Memory),a ROM (Read Only Memory), a RAM (Random Access Memory) or the like. Thestorage part 160 stores, for example, speed information 162, displayinformation 164, map information 166, a program read and executed by aprocessor, etc.

The speed information 162 includes, for example, information related toa speed range controllable by the driving controller 140 and informationrelated to the target vehicle speed of the vehicle M. The controllablespeed range refers to, for example, a range of speed estimated to becapable of automatically controlling the speed of the vehicle M in astate where the occupant does not operate the driving operator 80 (forexample, the accelerator pedal and the brake pedal) during downhilltraveling in the HDC. The speed range may be set variably depending onthe gradient angle of the road traveled and the vehicle type. The targetvehicle speed is a target value of the speed of the vehicle M in thespeed control of the driving controller 140. The target vehicle speedmay be adjusted by, for example, an operation of the accelerator pedalor the brake pedal performed by the occupant.

The display information 164 includes, for example, information relatedto a display mode of an image to be displayed on the display device 32according to the state of the driving control of the driving controller140. The display mode includes, for example, the type of the image (forexample, icon image and character image), color, size, line type andpattern of the image, character font, brightness of the image, presenceor absence of blinking display, presence or absence of animationdisplay, etc.

The map information 166 includes, for example, road shape (road gradientand curvature) and POI (Point Of Interest) information associated withthe position information (for example, latitude and longitude). Further,the map information 166 may include traffic regulation information suchas information on the center of the lane or information on the boundaryof the lane, address information (address/zip code), facilityinformation, telephone number information, etc. The map information 166may be updated at any time by the communication device of the vehicle Mcommunicating with an external device.

The recognition part 120 recognizes (detects) an object existing aroundthe vehicle M based on the information input from the camera 10 and theradar device 12. The object recognized by the recognition part 120 is athree-dimensional object or a two-dimensional object. Thethree-dimensional object includes, for example, a bicycle, a motorcycle,a four-wheeled vehicle, a pedestrian, a road sign, a utility pole, aguardrail, a falling object, etc. The two-dimensional object includes,for example, a road marking or a lane marking drawn on the road. Inaddition, the recognition part 120 recognizes a stop line, an obstacle,a red light, a tollhouse, and other road events. In the recognition, forexample, a recognition result based on the map information 166 may beadded.

In addition, the recognition part 120 recognizes the gradient angle ofthe road on which the vehicle M travels from the posture of the vehicleM detected by the vehicle sensor 40. Further, the recognition part 120may refer to the map information 166 based on the position of thevehicle M detected by the vehicle sensor 40 and acquire the gradientangle of the road associated with the position of the vehicle M.

The determination part 130 determines, for example, whether the startinstruction or the end instruction of the downhill travel control isreceived by the driving support switch 34, and whether the image is setto display or non-display by the display changeover switch 36. Further,the determination part 130 determines, for example, the state of thevehicle M based on the recognition result of the recognition part 120,and whether each condition for switching the state of the downhilltravel control (including, for example, the off state, the standbystate, the active state, etc.) is satisfied. Further, the determinationpart 130 outputs the determination result to the driving controller 140,and sets the driving controller 140 to the standby state or the activestate. The details of the function of the determination part 130 will bedescribed later.

The driving controller 140 includes, for example, a speed controller 142and a steering controller 144. For example, based on the determinationresult of the determination part 130, the driving controller 140operates one or both of the speed controller 142 and the steeringcontroller 144 to set to the standby state or the active state andexecute the driving control for the vehicle M. For example, in the caseof the active state, based on the recognition result of the recognitionpart 120 and the detection result of the vehicle sensor 40, the speedcontroller 142 controls the speed of the vehicle M to a constant speedby controlling one or both of the traveling driving force output device200 and the brake device 210 so that the speed of the vehicle Mapproaches the target vehicle speed within the controllable speed range.The “constant speed” may include a predetermined speed range. Forexample, assuming that the constant speed is 14 [km/h], a predeterminedspeed range of, for example, 13 to 15 [km/h] may be included. The speedcontroller 142 acquires information related to the speed range and thetarget vehicle speed from the speed information 162 of the storage part160. In addition, in the case of the standby state, based on theoperation of the accelerator pedal or the brake pedal of the drivingoperator 80 performed by the occupant, the speed controller 142 changes(adjusts) the target vehicle speed, and registers (updates) the changedtarget vehicle speed in the speed information 162.

For example, in the case of the active state, based on the recognitionresult of the recognition part 120 and the detection result of thevehicle sensor 40, the steering controller 144 controls the steeringdevice, etc. so that the vehicle M travels at a predetermined position.For example, when executing the LKAS control, based on the positioninformation of the vehicle M, the steering controller 144 controls thesteering device so that the vehicle M does not deviate from thetraveling lane. The processing of the speed controller 142 and thesteering controller 144 is realized by, for example, a combination offeedforward control and feedback control. In the case of the standbystate, the steering controller 144 may change the parameters requiredfor steering control based on the operation of the steering wheel SW ofthe driving operator 80 performed by the occupant. The information onthe above parameters may be stored in the storage part 160.

The traveling driving force output device 200 outputs a travelingdriving force (torque) for the vehicle M to travel to the drive wheels.The traveling driving force output device 200 includes, for example, acombination of an internal combustion engine, an electric motor, and atransmission, and a power ECU (Electronic Control Unit) that controlsthese. The power ECU controls the above configuration according to theinformation input from the driving controller 140 or the informationinput from the driving operator 80.

The brake device 210 includes, for example, a brake caliper, a cylinderthat transmits hydraulic pressure to the brake caliper, an electricmotor that generates hydraulic pressure in the cylinder, and a brakeECU. The brake ECU controls the electric motor according to theinformation input from the driving controller 140 or the informationinput from the driving operator 80 so that the brake torque according tothe brake operation is output to each wheel. The brake device 210 mayinclude, as a backup, a mechanism for transmitting the hydraulicpressure generated by the operation of the brake pedal included in thedriving operator 80 to the cylinder via a master cylinder. The brakedevice 210 is not limited to the configuration described above, and maybe an electronically controlled hydraulic brake device that controls anactuator according to the information input from the driving controller140 to transmit the hydraulic pressure of the master cylinder to thecylinder. Further, a regenerative brake of an electric motor included inthe traveling driving force output device 200 may be included.

The HMI controller 150 causes the HMI 30 to output various information.For example, the HMI controller 150 displays the operation informationrelated to the downhill road travel control on the display device 32.The details of the function of the HMI controller 150 will be describedlater.

Next, a display content according to the driving control of the vehiclesystem 1 will be specifically described. Hereinafter, the HDC will beused as an example of the driving control. In addition, the drivingsupport switch 34 receives the start instruction or the end instructionof the HDC. Further, in the following description, it is assumed thatthe first display part 32A is an indicator (IND) and the second displaypart 32B is an MID. FIG. 3 is a diagram for illustrating the HDCexecuted by the driving controller 140. In FIG. 3, it is assumed thatthe time t1 is the earliest time and the times t2, t3, t4, and t5 aredelayed in this order. Further, the position and the vehicle speed ofthe vehicle M at the time t* when the vehicle M travels on a downhillroad RD are respectively displayed as M(t*) and VM(t*).

In the example of FIG. 3, the occupant of the vehicle M operates thedriving support switch 34 at the time when the vehicle M startstraveling on the downhill road RD (the time t2 in the drawing) to givethe start instruction of the HDC. When the start instruction of the HDCis received by the driving support switch 34, the determination part 130determines the operation condition of the speed controller 142 and theexecution condition of speed control of the speed controller 142, andthe HDC is executed at the time when the operation condition and theexecution condition are satisfied (the time t3 in the drawing). In thiscase, the speed controller 142 controls the speed VM of the vehicle M toapproach the target vehicle speed within the controllable speed range sothat the speed VM becomes a constant speed. The constant speed mayinclude a predetermined speed range. For example, assuming that theconstant speed is 14 [km/h], a predetermined speed range of, forexample, 13 to 15 [km/h] may be included. The HMI controller 150displays the operation information according to the state of the drivingcontrol of the HDC on the display device 32.

FIG. 4 is a diagram showing an example of the images displayed on thedisplay device 32 at the times t1 to t3. The layout and display contentsof the images shown in FIG. 4 are not limited thereto. The same appliesto the following description of the images. First, at the time point ofthe time t1, the driving support switch 34 does not receive the startinstruction of the HDC (switch off state). Therefore, the HMI controller150 does not display anything on the IND and the MID.

Next, when the driving support switch 34 receives the start instructionof the HDC at the time point of the time t2, the HMI controller 150causes the IND and the MID to display the images indicating that thestart instruction of the HDC is received. The HMI controller 150 causesthe IND to display an abstract image IM10 showing the state of thevehicle M as an illustration. For example, the HMI controller 150displays an icon image (specifically, a state where the vehicle Mtravels downhill) indicating the HDC as the image IM10.

Further, the HMI controller 150 causes the MID to display an image IM20including a display area AR21 for displaying an image showing the stateof the vehicle M and a display area AR22 for displaying an imageindicating that the start instruction of the HDC is received. In thedisplay area AR21, for example, an abstract image (icon image) showingthe state of the vehicle M as an illustration is displayed, as the imageIM10. The same image as the image IM10 is displayed in the display areaAR21. In the display area AR22, information expressing the state of thevehicle M in characters is displayed, and for example, an image ofcharacter information such as “Hill Descent Control ON” that isinformation indicating that the start instruction of the HDC is receivedis displayed.

Next, the determination part 130 determines whether the operationcondition for operating the speed controller 142 is satisfied. Theoperation condition includes, for example, the following conditions (01)and (02).

Condition (01): a state where the vehicle M is not executing the drivingcontrol (for example, ACC).Condition (02): the speed VM of the vehicle M is equal to or lower thanthe predetermined speed. The predetermined speed refers to, for example,an upper limit value of the speed range controllable by the speedcontroller 142. For example, when the controllable speed range is 3 to20 [km/h], the predetermined speed is 20 [km/h]. The predetermined speedmay be changed according to the road surface condition and the gradientangle of the downhill road RD. Hereinafter, the controllable speed rangeis 3 to 20 [km/h], and the predetermined speed is 20 [km/h].

The determination part 130 determines that the operation condition issatisfied when the conditions (01) and (02) are satisfied, anddetermines that the operation condition is not satisfied when thecondition (01) or (02) is not satisfied. When it is determined that theoperation condition is satisfied, the driving controller 140 operatesthe speed controller 142. Then, the HMI controller 150 causes the MID todisplay a standby state image IM30 indicating that the downhill roadtravel control is in the standby state (execution standby state).

The standby state image IM30 includes display areas AR31 to AR34. In thedisplay area AR31, for example, an abstract image (icon image) showingthe state of the vehicle M as an illustration is displayed, as the imageIM10. The same image as the image IM10 is displayed in the display areaAR31. In the display area AR32, information expressing the state of thevehicle M in characters is displayed, and for example, an image ofcharacter information such as “Hill Descent Control Standby” that isinformation indicating that the speed controller 142 is in the standbystate is displayed. In the display area AR33, an image showing thetarget vehicle speed of the vehicle M in the HDC is displayed.

In the display area AR34, an image showing information related to thespeed of the vehicle M is displayed. The image showing the informationrelated to the speed of the vehicle M includes a first image IM31Ashowing the speed range controllable by the speed controller 142, asecond image IM31B showing the target vehicle speed of the vehicle M,and a third image IM31C showing the speed of the vehicle M. The firstimage IM31A is, for example, a speedometer image in which a scale isshown for each predetermined speed, and the speed range controllable bythe speed controller 142 is shown in a visible display mode. The secondimage IM31B and the third image IM31C are displayed at positionsassociated with the speeds shown in the speedometer image of the firstimage IM31A. That is, based on the display positions of the second imageIM31B and the third image IM31C, the occupant can recognize the currenttarget vehicle speed and the speed VM of the vehicle M from the scale ofthe first image IM31A.

In the example of FIG. 4, the second image IM31B is displayed at theposition of 14 [km/h] of the speedometer image, and the third imageIM31C is displayed at the position of 13 [km/h] of the speedometerimage. The display modes of the first image IM31A, the second imageIM31B, and the third image IM31C are not limited thereto. By displayingthe standby state image IM30 on the MID, the occupant can more clearlyrecognize the target vehicle speed and the speed VM of the vehicle Mwith respect to the speed range controllable by the speed controller142. For example, with one of the bar meters as the lower limit value ofthe controllable speed range and the other as the upper limit value ofthe controllable speed range, the target speed may be engraved on thescale of the bar meter, the current speed VM of the vehicle M may beindicated by a bar, and the color of the bar below the target speed andthe color of the bar above the target speed may be displayeddifferently.

When the determination part 130 determines that the above-describedoperation condition is satisfied, the HMI controller 150 displays theimage IM20 on the MID, and after a predetermined time (for example, 2seconds) elapses, displays the standby state image IM30. As a result, itis possible to prevent the occupant from missing the informationdisplayed on the image IM20. Further, the HMI controller 150continuously displays the image IM10 on the IND while the standby stateimage IM 30 is displayed.

In addition, when the determination part 130 determines that theabove-described operation condition is not satisfied, the HMI controller150 may display an error message on the display device 32. In this case,the HMI controller 150 displays information indicating the reason whythe speed controller 142 cannot be operated. For example, when theabove-described condition (01) is not satisfied, the HMI controller 150displays on the MID an image showing an error message such as “HDCcannot be executed because cruise control is in operation”. Further,when the above-described condition (02) is not satisfied, the HMIcontroller 150 displays on the MID an image showing an error messagesuch as “HDC cannot be started because the vehicle speed is high”. Inaddition to (or instead of) displaying the above-described images, theHMI controller 150 may output audio information corresponding to a partor all of the information included in the image from a speaker or thelike of the HMI 30. The same applies to the following description of theimages.

Next, the driving control and display control at the time t3 will bedescribed. The time t3 is the time when the HDC is executed. Thedetermination part 130 determines whether the execution condition of theHDC is satisfied in the standby state of the HDC. The executioncondition includes, for example, the following conditions (11) to (13).

Condition (11): a state where the occupant of the vehicle M is notoperating the accelerator pedal and the brake pedal of the drivingoperator 80. In other words, the input of the accelerator operation andthe brake operation is stopped.Condition (12): the gradient angle of the downhill road RD on which thevehicle M travels (for example, the gradient angle θ1 shown in FIG. 3)is equal to or greater than a predetermined angle (for example, 7degrees).Condition (13): the speed VM of the vehicle M is within the speed rangecontrollable by the speed controller 142.

The determination part 130 determines that the execution condition issatisfied when all the conditions (11) to (13) are satisfied, anddetermines that the execution condition is not satisfied when at leastone of the conditions (11) to (13) is not satisfied. For example, whenit is determined at the time t3 that the execution condition issatisfied, the driving controller 140 executes the HDC of the speedcontroller 142. Then, the HMI controller 150 causes the IND and the MIDto display images (hereinafter, active state image) showing that thetravel control of the speed controller 142 is in the active state(execution state).

FIG. 5 is a diagram showing an example of the images displayed on theIND and the MID at the time t3. When the travel control switches fromthe standby state to the active state, the HMI controller 150 displaysimages with different display modes with respect to the image IM10displayed on the IND and the standby state image IM30 displayed on theMID. The different display modes refer to, for example, differentcolors. In addition to (or instead of) changing the colors, thedifferent display modes may refer to differentiating the size, linetype, pattern, character font, and brightness of the image, or thedisplay modes may be differentiated by blinking display or animationimages.

For example, the HMI controller 150 causes the IND to display an activestate image IM11 in which the color of the image IM10 is changed from awhite color to a green or blue color. Further, the HMI controller 150causes the MID to display an active state image IM40 in which the colorof the image displayed in at least one of the display areas AR31 to AR34included in the standby state image IM30 is changed from a white colorto a green or blue color. The active state image IM40 includes displayareas AR41 to AR44. Images of contents corresponding to the contentsdisplayed in the display areas AR31 to AR34 are respectively displayedin the display areas AR41 to AR44. In the example shown, bydifferentiating the colors in the active state image IM11 and thedisplay areas AR41 and AR43 of the active state image IM40, it ispossible to easily attract the attention of the occupant.

In the display area AR41, an image in which the same icon image as theimage IM11 is expressed in a green color or a blue color is displayed.Further, in the display area AR42, for example, an image of characterinformation such as “Hill Descent Control Active” is displayed asinformation indicating that the downhill road travel control is in theexecution state (active state). In addition, in the display area AR44,at least one display mode, among the first image IM41A, the second imageIM41B, and the third image IM41C, is displayed differently from thedisplay mode in the standby state. In the example of FIG. 5, the HMIcontroller 150 displays the first image IM41A in a green or blue color,and displays the second image IM41B and the third image IM41C in thesame white color. When switching from the standby state to the activestate, by differentiating the display modes of the images displayed, theoccupant can more clearly recognize that the HDC is executed.

Next, an example of the display mode that changes according to whetherthe accelerator operation or the brake operation is performed will bedescribed. FIG. 6 is a diagram for illustrating an example of thedisplay mode that changes according to whether the accelerator operationor the brake operation is performed.

When the determination part 130 determines that the execution conditionis not satisfied because the conditions (12) and (13) are satisfied butthe condition (11) is not satisfied, the HDC is in the standby state,and the standby state images IM10 and IM30 are displayed on the displaydevice 32. When the operation on the accelerator pedal 81 or the brakepedal 82 is released in this state, the condition (11) is satisfied sothe HDC switches from the standby state to the active state. Thus, whenthe HDC is in the standby state and the input of the acceleratoroperation or the brake operation is stopped, the HMI controller 150displays by changing at least a part of the display mode of theoperation information in order to notify the occupant as such.

“Displaying by changing at least a part of the display mode of theoperation information” includes, for example, changing the mode (color,brightness of light, etc.) of the part where the display content doesnot change, and changing a part of the display content itself. As anexample of the former case, for example, the HMI controller 150 displaysthe active state images IM11 and IM40, which are partially green,instead of the standby state images IM10 and IM30, which are entirelywhite. As an example of the latter case, for example, the HMI controller150 displays the active state images IM11 and IM40 including the imageof character information such as “Hill Descent Control Active” insteadof the standby state images IM10 and IM30 including the image ofcharacter information such as “Hill Descent Control Standby”.

In many products, the white color often indicates standby and the bluecolor and the green color often indicate active. Therefore, it is easyto intuitively recognize the state of the HDC as compared with thedisplay in a single color. In addition, such a change in the displaymode requires less movement of the line of sight. Therefore, it ispossible to improve the safety of the occupant who confirms the displaycontent.

Not limited thereto, “displaying by changing at least a part of thedisplay mode of the operation information” may also include, afterdisplaying the standby state image, displaying a switching imagedifferent from the standby state image to display the active stateimage. The switching image may include, for example, an image thatdisplays a part of the display area in a color (for example, a redcolor) different from the white color of the standby state image and thegreen color or blue color of the active state image, and an image thatdisplays characters such as “HDC is activated by brake release”.

In addition, it is assumed that the accelerator pedal 81 or the brakepedal 82 is operated in a situation where all of the conditions (11) to(13) are satisfied, that is, the HDC is in the active state. In thiscase, the determination part 130 determines that the condition (11) isnot satisfied and the execution requirement of the HDC is not satisfied,and the HDC switches from the active state to the standby state. Thus,when the HDC is in the active state and the accelerator operation or thebrake operation is input, the HMI controller 150 displays by changing atleast a part of the display mode of the operation information in orderto notify the occupant as such. “Displaying by changing at least a partof the display mode of the operation information” is the same asdescribed above, and the detailed description thereof will be omitted.

Thus, by changing the display mode of the operation information inconjunction with the accelerator operation and the brake operationperformed by the occupant, the occupant can easily recognize that thestate of the HDC is switched, and can recognize that the cause isrelated to the accelerator operation or the brake operation performed bythe occupant.

Next, the display control when the target vehicle speed is changed(adjusted) in the period from the time t3 to the time t4 will bedescribed with reference to the drawing. The times t3a to t3g in thefollowing description indicate specific times in the period from thetimes t3 to t4.

FIG. 7 is a diagram for illustrating a first example of display controlwhen the target vehicle speed is changed. Further, the displaytransition of the MID when the target vehicle speed is set will bedescribed in the example of FIG. 7, and as for the IND, images (imagesIM10 and IM11) having the same display mode as the display areas AR31and AR41 are displayed. The same applies to the following description ofthe drawings.

For example, when the occupant P operates the brake pedal 82 at the timet3a (the brake on state) after the HDC (speed control) is executed bythe speed controller 142 at the time t3, the determination part 130determines that the execution condition of the HDC is not satisfied.Then, the driving controller 140 switches the HDC of the speedcontroller 142 from the active state to the standby state. In this case,the HMI controller 150 switches the display mode from the active stateimage IM40 to the standby state image IM30 and displays it on the MID.Thus, it is easy for the occupant P to recognize that the state of thedriving control of the vehicle M is changed.

Further, in the case of the standby state, the speed controller 142changes the target vehicle speed by making the target vehicle speedfollow the current vehicle speed VM of the vehicle M. In this case, theHMI controller 150 changes the display position of the third image IM31Cin the display area AR34 of the standby state image IM30 in accordancewith the speed of the vehicle M, and changes the numerical value of thetarget vehicle speed in the display area AR32 and the position of thesecond image IM31B in the display area AR34 according to the targetvehicle speed that is changed following the speed VM. Thus, it is easyfor the occupant P to recognize that the target vehicle speed is beingchanged.

For example, when the occupant P finishes the operation on the brakepedal 82 at the time t3b after the time t3a (the brake off state), thetarget vehicle speed is changed from 20 [km/h] to 14 [km/h] that followsthe vehicle speed VM, and the changed target vehicle speed is registeredin the speed information 162. When the execution condition of the HDC issatisfied at the time t3b, the speed controller 142 enters the activestate, and the HDC is executed with the target vehicle speed set to 14[km/h].

Here, when the brake operation ends, because all of the executionconditions (11) to (13) are satisfied, the HDC switches to the activestate. When the HDC of the speed controller 142 is executed, the HMIcontroller 150 switches from the standby state image IM30 to the activestate image IM40 and displays it on the MID. Thus, the occupant can moreclearly recognize the state of the vehicle M even in the control ofchanging the target vehicle speed. The example of FIG. 7 illustratesthat the target vehicle speed is changed by the operation on the brakepedal 82, but the target vehicle speed may also be changed by theoperation on the accelerator pedal 81.

Thus, even in the case of changing the target speed, when the HDC is inthe standby state and the input of the accelerator operation or thebrake operation is stopped or when the HDC is in the active state andthe accelerator operation or the brake operation is input, at least apart of the display mode of the operation information is changed anddisplayed, so that the occupant can be easily notified of the change ofthe state of the HDC, and the convenience for the occupant can beimproved.

FIG. 8 is a diagram for illustrating a second example of display controlwhen the target vehicle speed is changed. The second example shows anexample of display control when the target vehicle speed is changed to aspeed lower than the speed range controllable by the speed controller142. For example, as in FIG. 7, the speed VM of the vehicle is loweredby the operation of the occupant P on the brake pedal 82 at the timet3a, so that the function of following the target speed is activated andthe target vehicle speed is gradually reduced. When the vehicle speed VMbecomes lower than the lower limit (3 [km/h]) of the speed rangecontrollable by the speed controller 142 at the time t3c after the timet3a, the HMI controller 150 displays the numerical value of the targetvehicle speed in the display area AR33 of the standby state image IM30and the position of the second image IM31B in the display area AR34 byfixing them to the position associated with the lower limit (3 [km/h])of the controllable speed range. It is shown that the fixation of thesecond image IM31B is displayed in association with the lower limit ofthe first image IM31A. The position associated with the lower limit maybe the lower limit value itself, and may include, for example, aposition that is higher than the lower limit value by a predeterminedvalue and does not indicate the lower limit value or lower. Thus, it iseasy for the occupant P to recognize that the target vehicle speedcannot be changed to a speed lower than the lower limit value of thecontrollable speed range. When the operation on the brake pedal 82 isfinished in a state where the speed VM of the vehicle M is lower thanthe speed range, the target vehicle speed is changed to the lower limitvalue (3 [km/h]).

FIG. 9 is a diagram for illustrating a third example of display controlwhen the target vehicle speed is changed. The third example shows anexample of display control when the target vehicle speed is changed to aspeed higher than the speed range controllable by the speed controller142. For example, when the accelerator pedal 81 of the occupant P isoperated at the time t3d after the time t3 (the accelerator on state),the change of increasing the target vehicle speed is started based onthe operation of the accelerator pedal 81 in the standby state. Further,when the vehicle speed VM becomes higher than the upper limit (20[km/h]) of the speed range controllable by the speed controller 142 atthe time t3e after the time t3d, the HMI controller 150 displays thenumerical value of the target vehicle speed in the display area AR32 ofthe standby state image IM30 and the position of the second image IM31Bin the display area AR34 by fixing them to the position associated withthe upper limit (20 [km/h]) of the controllable speed range. It is shownthat the fixation of the second image IM31B is displayed in associationwith the lower limit of the first image IM31A.

Thus, it is easy for the occupant P to recognize that the target vehiclespeed cannot be changed to a speed higher than the upper limit value ofthe controllable speed range. Further, when the speed of the vehicle Mbecomes higher than 20 [km/h], the operation condition for entering thestandby state is not satisfied. Therefore, the HMI controller 150 causesthe second image IM31B to display information indicating that the hilldescent control cannot be operated and the reason. For example, amessage “Hill descent control cannot be operated: vehicle speed is toohigh” is displayed. In addition, the vehicle icon is changed to an icondisplayed with diagonal lines and cross marks superimposed to show thatthe hill descent control is not operating, and an illustration of thespeedometer is added and displayed next to it. Furthermore, the displayof the vehicle icon or the illustration portion of the speedometer maybe blinked. Further, the HMI controller 150 may also blink an imageshowing the target vehicle speed displayed in the display area AR32. Inthis way, the occupant P can be notified that the hill descent controlis not operating together with the reason. Moreover, by changing thedisplay mode with blinking or the like, the occupant P can be moreclearly notified that the speed VM exceeds the upper limit value of thespeed range. In addition, it is possible for the occupant P to preventexcessive speed during downhill traveling. When the speed VM of thevehicle M becomes higher than the speed range, the HMI controller 150may output a message urging to lower the speed VM. Further, the HMIcontroller 150 may perform the above-described blinking display on theimage displayed in association with the lower limit (3 [km/h]) of thecontrollable speed range shown in FIG. 8.

FIG. 10 is a diagram for illustrating an example of display control whenthe target vehicle speed is changed after the time t3e. The example ofFIG. 10 shows a state where the occupant P finishes the operation on theaccelerator pedal 81 (accelerator off) to operate the brake pedal 82(brake on), and finishes the operation on the brake pedal 82 (brake offstate) when the speed VM of the vehicle M is included in the speed rangecontrollable by the speed controller 142 between the times t3f and t3gafter the time t3e. When the speed VM of the vehicle M falls below theupper limit (20 [km/h]) of the speed range due to this operation, thedetermination part 130 determines that the execution condition of theHDC of the speed controller 142 is satisfied. The speed controller 142switches to the active state based on the determination result of thedetermination part 130. The HMI controller 150 causes the MID to displaythe active state image IM40 at the timing of entering the active state.

FIG. 11 is a diagram for illustrating display control based on a statechange of driving control after the time t4. For example, it is assumedthat the gradient angle θ1 of the downhill road RD on which the vehicleM travels is smaller than a predetermined angle at the time t4. In thiscase, the execution condition of the HDC is not satisfied, and thedriving controller 140 switches from the active state to the standbystate. The HMI controller 150 causes the MID to display the standbystate image IM30.

Further, when the driving support switch 34 receives the end instructionof the driving control (for example, driving support switch off) at thetime t5, the image IM20 is displayed on the MID. In the display areaAR22, an image of character information such as “Hill Descent ControlOFF” is displayed as information indicating that the driving supportswitch 34 is turned off. Then, the HMI controller 150 ends the displayof the image IM20 when a predetermined time (for example, 2 [seconds])elapses after displaying the image IM20.

On the other hand, if the driving support switch 34 does not receive theend instruction of the driving control, instead of turning off thedriving support switch 34, the driving controller 140 may forciblyterminate the HDC when the occupant P operates the accelerator pedal 81and the speed VM of the vehicle M exceeds a predetermined speed (forexample, 60 [km/h]). In this case, the HMI controller 150 causes the MIDto display an image IM50 showing that the HDC is terminated by the speedVM of the vehicle M exceeding the predetermined speed. In the example ofFIG. 11, because the speed VM of the vehicle M exceeds the predeterminedspeed at the time t5, the image IM50 is displayed.

The image IM50 includes an icon display area AR51 and a characterinformation display area AR52. In the icon display area AR51, anabstract image showing that the vehicle is going down a slope and anabstract image showing a speedometer are displayed. In the characterinformation display area AR52, an image showing character informationindicating that the control state of the vehicle M is changed isdisplayed. In the example of FIG. 11, character information such as“Hill descent control is turned off: vehicle speed is too high” isdisplayed in the character information display area AR52. Further, theHMI controller 150 ends the display of an image IM70 when apredetermined time elapses after displaying the image IM50. Thepredetermined time in this case may be the same as the predeterminedtime (for example, [2 seconds]) from the display of the image IM20 tothe end of the display, or may be a different time. Thus, it is easy forthe occupant P to know that the driving control of the drivingcontroller 140 is ended.

When the display changeover switch 36 receives an instruction to set thedisplay of the above-described image showing the state of the vehicle Mto non-display during operation (standby state) or execution (activestate) of the driving control, the HMI controller 150 may not displaythe standby state image and the active state image described above. Asdescribed above, the switching between the standby state and the activestate of the HDC is determined not based on the intention of theoccupant but based on the system side conditions such as the operationcondition and the execution condition. Therefore, the display switchingmay be annoying for some occupants. Hence, when the display changeoverswitch 36 receives the instruction of non-display, the display asdescribed above is not performed even if the state is switched. Inaddition, the HMI controller 150 may not display the image on the MIDbut continue to display the image on the IND. As a result, the occupantcan recognize the state of the vehicle M to a minimum level through theIND.

When the display changeover switch 36 receives an instruction to displaythe image again, the HMI controller 150 redisplays the image based onthe state (standby state and active state) of the vehicle M describedabove.

The HMI controller 150 may display operation information indicatingvarious driving control states on the display device 32, which is notlimited to the operation information described above. FIG. 12 and FIG.13 are diagrams showing other examples of the operation informationdisplayed on the display device 32.

For example, the above describes that nothing is displayed on the INDand the MID at the time point of the time t1 because of the switch offstate in which the driving support switch 34 does not receive the startinstruction of the HDC, but the disclosure is not limited thereto. Forexample, as shown in (A) of FIG. 12, both an image including thecharacters “Hill descent control OFF” and an icon image meaning the hilldescent control (an image showing a state where the vehicle M istraveling downhill) may be displayed close to each other. Here, in theimage shown in (A) of FIG. 12, the brightness of the character portionand the icon image is darker than a reference value. In this way, theoccupant can easily recognize the switch off state.

Further, when the driving support switch 34 receives the startinstruction of the HDC at the time t2 described above, as shown in (B)of FIG. 12, both an image including the characters “Hill descent controlON” and an icon image meaning the hill descent control (an image showinga state where the vehicle M is traveling downhill) may be displayedclose to each other. Here, in the image shown in (B) of FIG. 12, thebrightness of the icon image is brighter than the reference value, andthe brightness of the character portion is darker than the referencevalue. By increasing the brightness of the icon image in this way, theoccupant can intuitively recognize that some function is turned on, andcan easily recognize that the function turned on is hill descentcontrol.

In addition, when an error occurs because the above-described operationcondition is not satisfied, as shown in (C) of FIG. 12, both an imageincluding the characters “Hill descent control abnormal, system is notoperating” and an icon image meaning the hill descent control (an imageshowing a state where the vehicle M is traveling downhill) may bedisplayed close to each other in a red color. In this way, the occupantcan intuitively recognize that there is some abnormality from the iconimage displayed in red, and can easily recognize the reason as well.

In addition, when it is determined that the condition (01) is notsatisfied in the determination based on the above-described operationcondition, as shown in (A) of FIG. 13, an image including the characters“Hill descent control cannot be set: cruise control is in operation”, anicon image having a diagonal line that means impossible superimposed onan icon image meaning the hill descent control (an image showing a statewhere the vehicle M is traveling downhill), and an icon image meaningthe cruise control may be respectively displayed close to each other. Inthis way, the occupant can intuitively and easily recognize that thehill descent control is not executed and the reason is that the cruiseis in operation.

Further, when it is determined that the condition (12) is not satisfiedin the determination based on the above-described execution condition,as shown in (B) of FIG. 13, an image including the characters “Hilldescent control is canceled: gentle slope”, an icon image having adiagonal line that means impossible superimposed on an icon imagemeaning the hill descent control (an image showing a state where thevehicle M is traveling downhill), and an icon image showing a statewhere the vehicle M is traveling on a flat ground may be displayed closeto each other. In this way, the occupant can intuitively and easilyrecognize that the hill descent control being executed is ended and thereason is that the road on which the vehicle is traveling has becomeless sloping.

Further, when it is determined that the condition (13) is not satisfiedin the determination based on the above-described execution condition,as shown in (C) of FIG. 13, an image including the characters “Hilldescent control cannot be operated: speed is too high”, an icon imagehaving a diagonal line that means impossible superimposed on an iconimage meaning the hill descent control (an image showing a state wherethe vehicle M is traveling downhill), and an icon image meaning thespeedometer may be displayed close to each other. In this way, theoccupant can intuitively and easily recognize that the hill descentcontrol is not executed and the reason is that the vehicle speed is toohigh.

Further, when it is determined that the condition (02) is not satisfiedin the determination based on the above-described operation condition,as shown in (D) of FIG. 13, an image including the characters “Hilldescent control is turned off: speed is too high”, an icon image havinga diagonal line that means impossible superimposed on an icon imagemeaning the hill descent control (an image showing a state where vehicleM is traveling downhill), and an icon image meaning the speedometer aredisplayed close to each other. In this way, the occupant can intuitivelyand easily recognize that the hill descent control is not executed andthe reason is that the vehicle speed is too high.

[Processing Flow]

FIG. 14 is a flowchart showing an example of the flow of processingexecuted by the driving support device 100 of the embodiment. In thefollowing processing, the display control processing according to thecontent of the driving control performed by the driving controller 140will be mainly described. Furthermore, the following describes constantspeed travel control (HDC) on a downhill as an example of the drivingcontrol.

In the example of FIG. 14, the determination part 130 determines whetheran execution instruction of the HDC is received by the driving supportswitch 34, for example (step S100). When it is determined that theexecution instruction of the HDC is received, the HMI controller 150causes the display device 32 to display an image showing that the startinstruction of the HDC is received (step S110).

Next, the determination part 130 determines whether the operationcondition of the speed controller 142 is satisfied based on therecognition result of the recognition part 120 (step S120). When it isdetermined that the operation condition is satisfied, the drivingcontroller 140 operates the speed controller 142 to set to the standbystate (step S130). The HMI controller 150 causes the display device 32to display an image showing that the control of the speed controller 142is in the standby state (step S140).

Next, the determination part 130 determines whether the executioncondition of the HDC is satisfied (step S150). When it is determinedthat the execution condition is satisfied, the speed controller 142executes the HDC (step S160). The state where the HDC is being executedis the active state. Next, the HMI controller 150 causes the displaydevice 32 to display an image showing the execution state of the HDC(step S170).

Next, the determination part 130 determines whether the end instructionof the HDC is received by the driving support switch 34, for example(step S180). If it is determined that the end instruction of the HDC isreceived, the processing returns to step S150. If it is determined inthe process of step S150 that the execution condition is not satisfied,the determination part 130 determines whether the speed controller 142is in the active state (step S190). If it is determined that the speedcontroller 142 is in the active state, the state of the speed controller142 is switched to the standby state (step S200). When it is determinedthat the speed controller 142 is not in the active state after theprocess of step S200 or in the process of step S190, the determinationpart 130 determines whether the end instruction of the HDC is receivedby the driving support switch 34 (step S210). When it is determined thatthe end instruction of the HDC is not received, the processing returnsto step S140.

When it is determined in the process of step S180 or step S210 that theend instruction of the HDC is received, the HMI controller 150 causesthe display device 32 to display an image showing that the endinstruction is received (step S220). Thereby, the processing of thisflowchart is ended.

Furthermore, when it is determined in the process of step S120 that theoperation condition of the HDC is not satisfied, the HMI controller 150outputs an error message and ends the processing of this flowchart (stepS230). In addition, when it is determined in the process of step S100that the start instruction of the HDC is not received, the processing ofthis flowchart is ended.

In the embodiment, when the display changeover switch 36 receives aninstruction as to whether to display an image, processing of displayingor not displaying the image may be performed based on the receivedinstruction, in addition to the processing shown in FIG. 14.

Next, the flow of processing of changing the target vehicle speedexecuted when the speed controller 142 is in the standby state in theprocesses of step S130 and step S140 will be described. FIG. 15 is aflowchart showing an example of the flow of processing of changing thetarget speed. In FIG. 15, the HMI controller 150 causes the displaydevice 32 to display the standby state image, which includes the firstimage showing the speed range controllable by the speed controller 142,the second image showing the target vehicle speed, and the third imageshowing the vehicle speed (step S141). Next, the speed controller 142changes the target vehicle speed by following the speed VM of thevehicle M based on the operation of the occupant on the acceleratorpedal 81 or the brake pedal 82 (step S142). Next, the speed controller142 determines whether the speed VM of the vehicle M deviates from thespeed range controllable by the speed controller 142 (step S143). Whenit is determined that the speed VM deviates from the speed range, thespeed controller 142 determines whether the speed VM is higher than theupper limit of the speed range (step S144). When it is determined thatthe vehicle speed is higher than the upper limit of the speed range, theHMI controller 150 displays the second image by fixing it to theposition associated with the upper limit of the speed range of the firstimage (step S145), and blinks the second image to be displayed (stepS146). The display in step S145 corresponds to displaying the secondimage in association with the upper limit of the first image.

Furthermore, when it is determined in the process of step S143 that thespeed VM is not higher than the upper limit of the speed range, thespeed VM may be lower than the lower limit of the speed range.Therefore, the HMI controller 150 displays the second image by fixing itto the position associated with the lower limit of the speed range ofthe first image. This display corresponds to displaying the second imagein association with the lower limit of the first image. Moreover, whenit is determined in the process of step S143 that the speed of thevehicle does not deviate from the speed range, once the occupantfinishes the operation on the accelerator pedal 81 or the brake pedal82, the target vehicle speed for which the change is completed isregistered in the speed information 162 or the like (step S148). As aresult, the processing of this flowchart is ended. After the processesin steps S146 and S147 are ended, the processing may return to step S141to be continued. Further, in the process of step S144, instead ofdetermining whether the speed VM is higher than the upper limit of thespeed range, it may be determined whether the vehicle speed is lowerthan the lower limit of the speed range.

According to the above-described embodiment, in the display device (HMI30 and HMI controller 150), the operation information related to thedownhill road travel control is displayed on the display device, thedownhill road travel control is control for switching from the activestate to the standby state when the execution condition is satisfied,which includes that the input of the accelerator operation and the brakeoperation is stopped, and when the downhill road travel control is inthe standby state and the input of the accelerator operation or thebrake operation is stopped, at least a part of the display mode of theoperation information is changed and displayed, which makes it easy forthe occupant to recognize the state of the driving control.

Specifically, according to the embodiment, when the downhill road travelcontrol is in the standby state and the input of the acceleratoroperation or the brake operation is stopped, the active state image isdisplayed instead of the standby state image so it is easy to link withthe accelerator operation and the brake operation for the occupant tointuitively recognize the change of the control state. Since theoccupant does not have to pay attention to the display part and the lineof sight of the occupant is less moved, it is easy to concentrate ondriving.

Further, according to the embodiment, both the icon image showing thestate of the downhill road travel control and the wording image showingthe state of the downhill road travel control are displayed as theoperation information, by which the image as a momentary informationacquisition means and the wording display as a detailed informationacquisition means can be displayed in combination. Since the driver canchoose between rough information and detailed information according tothe situation, the burden of collecting information on the driver can bereduced.

Although the above-described embodiment mainly illustrates speed control(constant speed control) such as HDC, the disclosure may also beexecuted on steering control of the vehicle M, instead of (or inaddition to) the speed control. In that case, the operation conditionand execution condition described above are changed to conditions forsteering control.

The embodiment described above can be expressed as follows. A displaydevice mounted on a vehicle includes a storage device that stores aprogram, a hardware processor, and a display part. The hardwareprocessor executes the program stored in the storage device, by whichoperation information related to downhill road travel control thatcontrols a speed of the vehicle traveling downhill to a constant speedis displayed on the display part. The downhill road travel control iscontrol for switching from a standby state to an active state when anexecution condition including that input of an accelerator operation anda brake operation is stopped is satisfied. When the downhill road travelcontrol is in the standby state and the input of the acceleratoroperation or the brake operation is stopped, at least a part of adisplay mode of the operation information is changed and displayed.

The forms for implementing the disclosure have been described aboveusing the embodiments, but the disclosure is not limited to theseembodiments, and various modifications and substitutions can be addedwithout departing from the gist of the disclosure.

What is claimed is:
 1. A display device mounted on a vehicle, thedisplay device comprising: a display part; and a display controllerdisplaying operation information related to downhill road travelcontrol, which controls a speed of the vehicle traveling downhill to aconstant speed, on the display part, wherein the downhill road travelcontrol is control that switches from a standby state to an active statewhen an execution condition, which comprises that input of anaccelerator operation and a brake operation is stopped, is satisfied,and the display controller displays by changing at least a part of adisplay mode of the operation information when the downhill road travelcontrol is in the standby state and the input of the acceleratoroperation or the brake operation is stopped.
 2. The display deviceaccording to claim 1, wherein the display controller displays a standbystate image showing that the downhill road travel control is in thestandby state when the downhill road travel control is in the standbystate, and displays an active state image having a different displaymode from the standby state image and showing that the downhill roadtravel control is in the active state when the downhill road travelcontrol is in the active state, and displays the active state imageinstead of the standby state image when the downhill road travel controlis in the standby state and the input of the accelerator operation orthe brake operation is stopped.
 3. The display device according to claim1, wherein the display controller displays by changing at least a partof the display mode of the operation information when the downhill roadtravel control is in the active state and the accelerator operation orthe brake operation is input.
 4. The display device according to claim2, wherein the display controller displays by changing at least a partof the display mode of the operation information when the downhill roadtravel control is in the active state and the accelerator operation orthe brake operation is input.
 5. The display device according to claim3, wherein the display controller displays the standby state imageshowing that the downhill road travel control is in the standby statewhen the downhill road travel control is in the standby state, anddisplays the active state image having a different display mode from thestandby state image and showing that the downhill road travel control isin the active state when the downhill road travel control is in theactive state, and displays the standby state image instead of the activestate image when the downhill road travel control is in the active stateand the accelerator operation or the brake operation is input.
 6. Thedisplay device according to claim 4, wherein the display controllerdisplays the standby state image showing that the downhill road travelcontrol is in the standby state when the downhill road travel control isin the standby state, and displays the active state image having adifferent display mode from the standby state image and showing that thedownhill road travel control is in the active state when the downhillroad travel control is in the active state, and displays the standbystate image instead of the active state image when the downhill roadtravel control is in the active state and the accelerator operation orthe brake operation is input.
 7. The display device according to claim2, wherein the standby state image is an image that displays at leastpart of the operation information in a white color, and the active stateimage is an image that displays at least part of the operationinformation in a green color.
 8. The display device according to claim5, wherein the standby state image is an image that displays at leastpart of the operation information in a white color, and the active stateimage is an image that displays at least part of the operationinformation in a green color.
 9. The display device according to claim1, wherein the display controller displays both an icon image showing astate of the downhill road travel control and a wording image showingthe state of the downhill road travel control as the operationinformation.
 10. The display device according to claim 2, wherein thedisplay controller displays both an icon image showing a state of thedownhill road travel control and a wording image showing the state ofthe downhill road travel control as the operation information.
 11. Thedisplay device according to claim 3, wherein the display controllerdisplays both an icon image showing a state of the downhill road travelcontrol and a wording image showing the state of the downhill roadtravel control as the operation information.
 12. The display deviceaccording to claim 4, wherein the display controller displays both anicon image showing a state of the downhill road travel control and awording image showing the state of the downhill road travel control asthe operation information.
 13. The display device according to claim 5,wherein the display controller displays both an icon image showing astate of the downhill road travel control and a wording image showingthe state of the downhill road travel control as the operationinformation.
 14. The display device according to claim 6, wherein thedisplay controller displays both an icon image showing a state of thedownhill road travel control and a wording image showing the state ofthe downhill road travel control as the operation information.
 15. Thedisplay device according to claim 7, wherein the display controllerdisplays both an icon image showing a state of the downhill road travelcontrol and a wording image showing the state of the downhill roadtravel control as the operation information.
 16. The display deviceaccording to claim 8, wherein the display controller displays both anicon image showing a state of the downhill road travel control and awording image showing the state of the downhill road travel control asthe operation information.
 17. A display control method for a computerof a display device mounted on a vehicle to display operationinformation related to downhill road travel control, which controls aspeed of the vehicle traveling downhill to a constant speed, on adisplay part, wherein the downhill road travel control is control thatswitches from a standby state to an active state when an executioncondition, which comprises that input of an accelerator operation and abrake operation is stopped, is satisfied; and display by changing atleast a part of a display mode of the operation information when thedownhill road travel control is in the standby state and the input ofthe accelerator operation or the brake operation is stopped.
 18. Anon-transitory computer-readable recording medium recording a programfor a computer of a display device mounted on a vehicle to displayoperation information related to downhill road travel control, whichcontrols a speed of the vehicle traveling downhill to a constant speed,on a display part, wherein the downhill road travel control is controlthat switches from a standby state to an active state when an executioncondition, which comprises that input of an accelerator operation and abrake operation is stopped, is satisfied; and display by changing atleast a part of a display mode of the operation information when thedownhill road travel control is in the standby state and the input ofthe accelerator operation or the brake operation is stopped.